The embodiments of the present invention relates to a sound processing apparatus and method suited for use in, for example, audio mixers and the like.
Audio mixers (hereinafter referred to simply as “mixers”) installed, for example, in concert venues and the like are generally constructed in such a manner that respective volume of sound signals (audio signals) input to individual channels are adjusted by faders of the channels, the volume-adjusted sound signals are output selectively to buses, the sound signals supplied from one or more of the channels are mixed in each of the buses, and the mixed results are output to output destinations. The output destinations of such a mixer are, for example, a main speaker oriented toward audience seats in the concert venue, a monitor speaker for a human player or players on the stage, and external equipment, such as a recording device and an effecter device.
Among the conventionally known mixers is one that is capable of setting, for each input channel and for each output bus, a “pre-fader mode” in which a sound signal before being subjected to volume adjustment by a fader is supplied to the output bus or a “post-fader mode” in which a sound signal after having been subjected to the volume adjustment by the fader is supplied to the output bus. A human operator of the mixer can select one of the post-fader sound signal and the pre-fader sound signal as a sound signal to be output, for example, to a monitor speaker, an effecter device, and the like.
For example, the human operator uses the post-fader mode when he or she wants to change volume (sound volume) of a sound signal to be sent to a given output bus in synchronism with the volume adjustment by the fader, but uses the pre-fader mode when he or she does not want to change the volume of the sound signal in synchronism with the volume adjustment by the fader. More specifically, when a human player's own performance sound is to be output, for example, to the monitor speaker for human players on the stage, the pre-fader mode is used with respect to an output bus for the monitor speaker. Further, when a reproduced sound of a CD or the like is to be sent to the monitor speaker for human players, or when a performance sound is to be sent to an external effecter device, for example, the post-fader mode is often used with respect to the corresponding output bus.
Switching between the pre-fader mode and the post-fader mode as above is convenient in that a sound signal to be sent to an output bus can be selected as necessary depending on an intended use of an output destination. However, the conventionally known mixer construction would present the problem that when switching has been made between the pre-fader mode and the post-fader mode, the volume of the sound signal to be sent to the output bus changes by an amount of the volume adjustment by the fader. For example, when switching has been made from the pre-fader mode to the post-fader mode in the case where the volume of the sound signal is increased by the fader, the volume of the sound signal of the post-fader mode to be output to the corresponding output bus increases by the amount of the volume adjustment by the fader as compared with the sound signal of the pre-fader mode before the switching. Conversely, when switching has been made from the post-fader mode to the pre-fader mode, the volume of the sound signal of the pre-fader mode to be output to the corresponding output bus decreases by the amount of the volume adjustment by the fader as compared with the sound signal of the post-fader mode before the switching. Such a sound volume change not intended by the human operator would cause inconveniences, such as giving an uncomfortable feeling to listeners or audience.